Description of problem:
This used to work just fine - but someone broke it along the way by trying to be
clever. Anyway, attached patch uses internal linux byteswap functionality when
requested in place of broken 'asm' 

Version-Release number of selected component (if applicable):
1.6.8-0.10.rc2

How reproducible:
Try loading an SGI image file - you will get an INVALID HEADER error because the
header values are not converted from big endian to little endian (when required)

Steps to Reproduce:
1.
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Actual results:
Image file doesn't load

Expected results:
Image file should load!

Additional info:
I can attach an sgi rgb file for testing - but the patch I included works as
long as it is added to the spec file.